Extra-thyroid extension increases the risk for disease recurrence in adults with differentiated thyroid cancer compared with those without extension, but overall mortality is higher in those without extension, study data show.
Eyal Robenshtok, MD, of the Endocrine Institute at Rabin Medical Center-Beilinson Hospital and the Sackler Faculty of Medicine at Tel Aviv University in Israel, Talia Diker-Cohen, MD, PhD, of the Institute of Endocrinology, Diabetes and Metabolism at Rabin Medical Center-Beilinson Hospital in Israel, and colleagues conducted a systematic review and meta-analysis of 13 studies published between 1966 and June 2017 with a median follow-up of 86 months that included 23,816 adults with differentiated thyroid cancer to determine the effect of minimal extra-thyroid extension on disease outcome. Participants with and without lymph node metastases were included. Recurrent or persistent disease at the end of follow-up, disease-related mortality and overall mortality were the primary outcomes.
Among participants without lymph node metastases, the risk for recurrence was increased among those with minimal extra-thyroid extension compared with those without extension (OR = 1.73; 95% CI, 1.03-2.92). Participants with tumor extension had a higher absolute risk for recurrence compared with those without extension (3.5% vs. 2.2%; P = .04). Further, the risk for recurrence was higher in participants with extension who underwent lobectomy alone compared with those without extension who underwent lobectomy alone (6.9% vs. 4.2%; P = .3).
Among a combination of participants with and without lymph node metastases, the risk for recurrence was higher among those with extension compared with those without extension (OR = 1.82; 95% CI, 1.14-2.91). The absolute risk for recurrence was also higher in those with extension compared with those without extension (7% vs. 6.2%; P = .01). In participants with or without lymph node metastases who underwent total thyroidectomy or radioactive iodine ablation, the risk for recurrence was higher in those with extension compared with those without extension (4.8% vs. 2.3%; P = .06).
Among participants with micropapillary thyroid carcinoma, minimal extra-thyroid extension had no significant effect on recurrence rates.
Participants with extension had lower overall mortality compared with those without extension (8.7% vs. 9.8%).
“For many years, minimal extra-thyroid extension was regarded as an indication for total thyroidectomy and radioiodine ablation, due to fear of high risk for recurrence,” Robenshtok told Endocrine Today. “Our study strongly demonstrates that though the risk is slightly higher, it is still within the low-risk category. This implies that patients with minimal extra-thyroid extension with lymph node involvement may be treated less aggressively — either without radioiodine or with lobectomy alone. This approach is in line with the current paradigm of less-aggressive treatment in patients with low-risk thyroid cancer, balancing the benefit of treatment with treatment-related morbidity. We need to look at the patient as a whole, looking to cure disease while preserving optimal quality of life. Given how common minimal extra-thyroid extension is, this data may have a substantial effect on treatment recommendations.” – by Amber Cox
For more information:
Eyal Robenshtok, MD, can be reached at firstname.lastname@example.org.
Disclosures: The authors report no relevant financial disclosures.